JSON Formatter & Validator
Format, validate and minify JSON instantly — 100% in your browser.
About JSON Formatter & Validator
Paste your JSON below and it is instantly parsed, validated and pretty-printed. If the JSON is invalid, you get the exact error and position so you can fix it fast.
Everything runs locally in your browser using the native JSON parser — your data is never sent to a server, which makes it safe for API responses, config files and other sensitive payloads.
Format compact JSON
{"name":"Ada","langs":["en","fr"],"active":true}{
"name": "Ada",
"langs": [
"en",
"fr"
],
"active": true
}Switch the indent selector to 2/4 spaces or tabs, or use Minify to strip whitespace.
Frequently asked questions
Is my JSON uploaded to a server?
No. Parsing and formatting happen entirely in your browser, so your data never leaves your device.
What does the validator check?
It uses the browser's native JSON parser, so it flags any syntax that isn't valid JSON — trailing commas, unquoted keys, single quotes, and so on — with the error message and location.
Can it minify JSON too?
Yes. The Minify option removes all insignificant whitespace to produce the smallest valid JSON output.